1. The grooves of the positioning sleeves of the engaging sleeves should be repaired or replaced with new ones if excessive wear occurs. 2. Replace the spring with too small spring or broken spring with standard spring to ensure that the engaging sleeve has sufficient positioning stability and reliability. 3. When the pull-out groove and the joystick ball head are excessively worn, the heat treatment can be performed after the manual trimming. Replacement of new parts that cannot be repaired. 4, when the clutch meshing teeth bald should be promptly repaired or replaced. The repair can be used carbon copper electrode welding meshing teeth and then standard tooth indentation after welding repair and heat treatment as required.